Figure 7.

β₃-Adrenergic receptor stimulation promotes antidiuresis in mice lacking functional expression of the arginine vasopressin receptor type 2. Ten V2R^fl/yEsr1-Cre mice were acclimatized in mouse metabolic cages for 48 hours; 5 received a single i.p. injection of BRL37344 (0.6 mg/kg), whereas 5 control mice received phosphate-buffered saline alone (vehicle). Urine samples were collected every hour for 3 hours from both groups, and urine output (a) and urine osmolality (b) at each time point were reported. One hour after the injection, the urine output of BRL37344-treated mice was reduced to zero compared with vehicle-injected animals (vehicle) (diuresis, 1 hour). Two hours after injection, urine output of treated mice was still dramatically reduced compared with control animals (diuresis, 2 hours). Urine osmolality increased in BRL37344-injected animals (urine osmolality, 2 hours). At 3 hours postinjection, the effect of BRL on the urine output still persisted (urine output, 3 hours), whereas the effect on urine osmolality partially reversed (urine osmolality, 3 hours). The analysis reports the mean ± SEM values. Significant differences between measurements were tested by 2-way analysis of variance with a Bonferroni posttest for diuresis and by 1-way analysis of variance with a Bonferroni posttest. *P < 0.05; ***P < 0.001.